<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>


    <script>
        // var 全局作用域
        var num = 1;
        var str = "zs";
        var list = ["zs", "ls"];
        var user = {
            name : "zs",
            age: 18
        };
        var chr = 'c';


        // ES6中:  (ECMAScript6: 2015 )

        // let局部作用
        let i = 1;
        let str = 'zs'

        // const 定义了之后不允许修改
        const i = 2;
        const str = "ls"


    </script>
</body>
</html>
